Medical devices which are implanted in a mammal body, such as the human body, can be used to replace or supplement a large variety of bodily functions or organs.
Since it usually is difficult or uncomfortable to access a device which has been implanted in a mammal body, such devices are usually arranged to use a power source which supplies the implanted device with power in a wireless fashion, either in order to power the device directly, or in order to charge a rechargeable energy source such as an electrochemical cell or battery in the device.
In a medical device which is implanted in a mammal body, the function of the device is naturally of paramount importance. If an implanted device malfunctions, it is desirable for the user of the device, or somebody in their immediate vicinity, to be capable of overcoming such a malfunction, at least until the user has received proper help from medical professionals.
Methods and devices for charging a rechargeable energy source are e.g. disclosed in the published U.S. patent application 2005/0075697 and U.S. Pat. Nos. 5,690,693, 5,702,431, 5,713,939 and 6,456,883.